1. Field of the Invention
The present invention generally relates to structures used in blind riveting apparatus and, in particular, those apparatus adapted for automatic insertion techniques.
2. Prior Art
There are many devices disclosed in the prior art which are generically described as blind rivets. The typical blind rivet disclosed in the prior art utilizes a hollow metal rivet member having a preformed rivet head at one end thereof. A pulling stem or mandrel member of metal being able to withstand higher axial stress than the material of the rivet is also provided, the mandrel being sized to pass through the interior of the hollow rivet. The mandrel has a rivet forming head which is adapted to be cooperatively engaged with the portion of the rivet member opposite the preformed rivet head. By pulling the mandrel through the rivet, the portion of the rivet body in contact with the rivet forming head of the mandrel is forced back thereby producing a rivet head which typically binds a pair of overlapping members into an integral assembly.
The devices disclosed by the prior art typically have one characteristic in common, that being the need for a pulling stem or mandrel to form a rivet head opposite the preformed rivet head of the rivet body. The mandrel used by these devices may differ in shape and content, but all typically provide the force needed to deform the malleable material of the rivet body into a formable rivet head.
Another feature which is typically represented by the devices disclosed in the prior art is the individual nature of the rivet assembly as opposed to a structure which is adapted for automatic insertion techniques. The devices disclosed in the prior art comprise a rivet body having a cooperating mandrel or pulling stem disposed therethrough, the combination of elements comprising the blind rivet and mandrel being adapted only for manual insertion within a workpiece and formation of the rivet head thereafter.
The problems which remain inherent in the devices disclosed by the prior art center on the required use of a pulling stem or mandrel as well as the inability of the prior art devices to be easily used with automatic insertion equipment. The present invention substantially resolves the problems which have heretofore remained unsolved by the devices disclosed in the prior art.
The present invention comprises a blind rivet apparatus which requires no mandrel or pulling stem and the insertion tool for use with same. The structure of the present invention comprises a carrier element in combination with rivet bodies which are uniformly disposed along the longitudinal dimension of the carrier element. The carrier element and integral rivet body are adapted to be used with an insertion tool which is typically a portion of automatic insertion apparatus. In all forms of the present invention, the insertion apparatus used for separating the rivet body from the carrier element causes formation of the rivet head from the rivet body itself. In this manner, rivet bodies may be properly oriented and registered with respect to a given workpiece and be disposed within and formed into a rivet without the requirements of those devices disclosed in the prior art. In this manner, a blind rivet apparatus is adaptable for automatic insertion techniques, the device eliminating the wasteful and costly need for a pulling stem or mandrel as required by the devices disclosed in the prior art.